[Amps] 240V Outlet

[jimsmitheguard-a at yahoo.com]

Correct, but I was trying not to complicate the matter more. This applies to continuous loads. That's something intended to run more than 3 hours straight.
 
The data centers usually have 100% rated breakers on the feeders to avoid this derating, but not on the branch circuits.
 
Jim Smith, EE
KQ6UV

--- On Wed, 8/12/09, Scott McGrath <mcgrath at fas.harvard.edu> wrote:


From: Scott McGrath <mcgrath at fas.harvard.edu>
Subject: Re: [Amps] 240V Outlet
To: "jimsmitheguard-a at yahoo.com" <jimsmitheguard-a at yahoo.com>, "amps at contesting.com" <amps at contesting.com>
Date: Wednesday, August 12, 2009, 5:28 PM


One fact lost in the 15 vs 20 amp outlet discussion is the NEC requires you to derate any circuit to 80pct of its full load capacity for loads which are steady state.   So a 20A circuit is allowed only to have 16A drawn.   In data centers we have to abide by this rule